Flow control valves, dampers and steering devices

Abstract

Provided are a steering device capable of absorbing large impact forces, a damper applicable to the steering device, and a flow control valve applicable to the damper. The steering device (100) includes a damper (120) between a rack rod (103) and a rack ball joint mechanism (106). The damper (120) is formed with an inner cavity (121) on the outer periphery of a socket body (107) and is provided for a one-piece displacement body (130) to be slidably engaged. In the one-piece displacement body (130), a flow control valve (140) is formed in an annular shape on the inner periphery. A first flow control valve (150) is provided in the flow control valve (140). The first flow control valve (150) includes a second flow body (156) that is close to or away from the first flow body (153). The second flow body (156) is formed with a second flow hole (157) at a position offset from the first flow hole (154) formed in the first flow body (153), and a second aperture restriction portion (158) blocks the first flow hole (154).

Description

Technical Field

[0001] The present invention relates to a flow control valve provided in a flow path through which a fluid flows and which controls the flow of the fluid by restricting the flow of the fluid, a damper including the flow control valve, and a steering device including the damper. Background Art

[0002] Conventionally, four-wheeled self-propelled vehicles have a steering system as a mechanical device for transmitting the driver's steering operation to the wheels to steer the vehicle. In this case, the steering system is equipped with a shock-absorbing member to absorb strong impacts, such as when the self-propelled vehicle drives over a curb. For example, Patent Document 1 below discloses a steering system that incorporates a shock-absorbing member made of rubber and metal between a rack housing covering the rack shaft and a tie rod connected to the wheel. This allows the system to absorb strong impacts, such as when the self-propelled vehicle drives over a curb.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-97840

[0004] However, the steering device disclosed in Patent Document 1 has a problem in that the magnitude of the shock that can be absorbed is small because the shock absorbing member is made of rubber or synthetic resin. Summary of the Invention

[0005] The present invention has been made to address the above-mentioned problems, and an object of the present invention is to provide a steering device capable of absorbing a large impact force, a damper applicable to the steering device, and a flow control valve applicable to the damper.

[0006] In order to achieve the above-mentioned purpose, the present invention is a flow control valve, which is arranged in a flow path for fluid flow, restricts the flow of the fluid and controls the flow of the fluid, and is characterized in that it comprises: a first flow body, having a first flow hole for fluid flow; a second flow body, arranged opposite to the first flow body, having a second flow hole for fluid flow; and a separation elastic body, which exerts elastic force in a manner that separates the first flow body and the second flow body from a position of mutual contact, and at least one of the first flow body and the second flow body has an aperture limiting portion, which blocks the second flow hole and at least a portion of the flow hole of at least one of the first flow holes when the first flow body and the second flow body are in contact with each other.

[0007] According to the features of the present invention thus constituted, the flow control valve includes an aperture restriction portion in at least one of a first flow body and a second flow body, each of which has a first flow hole and a second flow hole through which a fluid flows. The aperture restriction portion blocks at least a portion of at least one of the second flow hole and the first flow hole when the first flow body and the second flow body come into contact with each other. Thus, the flow control valve of the present invention can constitute a steering device that, when a large external force acts between the first flow body and the second flow body, restricts the flow of the fluid by blocking at least a portion of the first flow hole and the second flow hole with the aperture restriction portion, thereby attenuating the large external force and absorbing the large impact force.

[0008] In this case, the flow control valve of the present invention can freely adjust the conditions for blocking the first and second flow holes, that is, the magnitude and conditions for generating the damping force, by appropriately selecting the diameter of the second flow hole and the elastic force of the separation elastic body. Furthermore, the cross-sectional shape of each of the first and second flow holes can include shapes other than circular (including elliptical), such as square, polygonal, or various other irregular shapes.

[0009] Furthermore, in addition to the above-mentioned flow control valve, another feature of the present invention is that the aperture restriction portion is provided only on one of the first flow body and the second flow body.

[0010] According to another feature of the present invention thus constituted, since the aperture restriction portion of the flow control valve is provided only on one of the first flow body and the second flow body, the structure and manufacturing process of the flow control valve can be simplified.

[0011] Furthermore, in addition to the above-mentioned flow control valve, another feature of the present invention is that the aperture restriction portion is provided on both the first flow body and the second flow body.

[0012] According to another feature of the present invention thus constituted, since the aperture restriction portion of the flow control valve is provided on both the first flow body and the second flow body, the reliability of the control of the fluid flow can be improved.

[0013] Furthermore, in addition to the above-mentioned flow control valve, another feature of the present invention is that the aperture restriction portion is formed so as to completely block at least one of the second flow hole and the first flow hole.

[0014] According to another feature of the present invention thus constructed, since the aperture restriction portion of the flow control valve is formed to completely block at least one of the second flow hole and the first flow hole, a steering device capable of attenuating large external forces and absorbing large impact forces can be constructed.

[0015] In addition, based on the above-mentioned flow control valve, another feature of the present invention is that it also has a second flow body accommodation portion, which accommodates the second flow body on the second flow body side so that it is movable relative to the first flow body, and the separation elastic body is arranged between the first flow body and the second flow body in the second flow body accommodation portion.

[0016] According to another feature of the present invention thus constituted, the second flow body of the flow control valve is slidably accommodated in the second flow body accommodation portion, and thus the second flow body can be stably moved toward or away from the first fluid.

[0017] Furthermore, in addition to the above-mentioned flow control valve, another feature of the present invention is that the opening of the second flow body on the opposite side of the first flow body in the second flow hole is formed into a tapered shape in which the hole size decreases from the opening side toward the inner side.

[0018] According to another feature of the present invention thus constructed, the opening portion of the second flow hole in the second flow body of the flow control valve, on the side opposite to the first flow body, is formed into a tapered shape, with the hole size decreasing from the opening side toward the back. This facilitates fluid flow into the second flow hole compared to a straight second flow hole, thereby stabilizing the operation of the flow control valve. Furthermore, the flow control valve facilitates fluid flow into the second flow hole, increasing the flow rate. The tapered portion receives a strong pressing force from the fluid, facilitating displacement of the second flow body toward the first flow body.

[0019] In addition, based on the above-mentioned flow control valve, another feature of the present invention is that it also has a one-way valve that allows the fluid to flow in a flow path different from the first flow body and the second flow body. The one-way valve allows the fluid to flow from the first flow body side to the second flow body side and prevents the fluid from flowing from the second flow body side to the first flow body side.

[0020] According to another feature of the present invention thus constructed, the flow control valve includes a one-way valve separately from the first and second flow bodies. This one-way valve allows fluid to flow from the first flow body side to the second flow body side, while preventing fluid from flowing from the second flow body side to the first flow body side. Therefore, when fluid flows from the second flow body side to the first flow body side, the flow control valve of the present invention can actively cause the fluid to flow to the second flow body side, thereby facilitating displacement of the second flow body. Furthermore, when fluid flows from the first flow body side to the second flow body side, the flow control valve of the present invention can more efficiently cause fluid to flow from the first flow body side to the second flow body side, in addition to the one-way valve in the first and second flow bodies.

[0021] In addition, based on the above-mentioned flow control valve, another feature of the present invention is that it also has a flow restriction valve, which restricts the flow of fluid in a flow path different from the first flow body and the second flow body to allow it to circulate, and the flow restriction valve restricts the flow of fluid between the first flow body side and the second flow body side to allow it to circulate.

[0022] According to other features of the present invention constructed in this manner, since the flow control valve is provided with a flow restriction valve separately from the first flow body and the second flow body to restrict the flow of the fluid between the first flow body side and the second flow body side, it is possible to construct a flow control valve that has a basic damping force separately from the first flow body and the second flow body when the fluid flows between the first flow body side and the second flow body side.

[0023] Furthermore, the present invention can be implemented not only as an invention of a flow control valve but also as an invention of a damper including the flow control valve and a steering device including the damper.

[0024] A damper may be a damper, specifically comprising an inner cavity-forming body forming an inner cavity for fluid-tightly containing a fluid, and attenuating external forces acting on the fluid by restricting the flow of the fluid. The damper may include the flow control valve according to any one of claims 1 to 8, wherein the flow control valve restricts the flow of the fluid. Thus, the damper of the present invention can expect the same operational effects as the aforementioned flow control valve.

[0025] In this case, in addition to the above-mentioned damper, a reset elastic body can also be provided, which imparts an elastic force for causing the fluid to flow from the first flow body side to the second flow body side in the flow control valve. The flow control valve is arranged in the inner cavity in a state where it can be relatively displaced relative to the inner cavity. The reset elastic body imparts an elastic force to one of the inner cavity forming body and the flow control valve to cause the one to displace relative to the other.

[0026] Thus, the damper's return elastic body applies a spring force to one of the inner cavity-forming body and the flow control valve, displacing the other relative to the other. Consequently, when fluid is not flowing from the second flow-forming body to the first flow-forming body, the damper can displace the flow control valve relative to the inner cavity-forming body, maintaining the flow control valve in a position enabling fluid flow from the first flow-forming body to the second flow-forming body, i.e., an operating start position for the flow control valve to exert its damping function.

[0027] In addition, in the above case, on the basis of the above damper, it can also be provided with an integral displacement body, which is relatively displaced together with the flow control valve relative to the inner cavity, the inner cavity forming body is formed into a solid rod or cylinder, and the inner cavity is formed into a circular cylindrical shape on the outside of the inner cavity forming body, the flow control valve is formed on an annular valve support body, and the annular valve support body is embedded in the circular cylindrical inner cavity, and the integral displacement body is formed into a cylindrical shape that is embedded in the inner cavity forming body in a slidable manner.

[0028] Thus, since the inner cavity is formed outside the inner cavity forming body, the damper of the present invention can have the inner cavity forming body itself formed into a solid rod or cylindrical shape, thereby providing a wide variety of damper configurations. Furthermore, the inner cavity being formed into an annular cylindrical shape means an annular cylindrical shape having a circular cross-section and extending in a cylindrical shape.

[0029] In addition, in the above case, on the basis of the above damper, it can also be provided with an integral displacement body, which is relatively displaced together with the flow control valve relative to the inner cavity, the inner cavity forming body is formed into a cylindrical shape, and the inner cavity is formed into a circular cylindrical shape on the inner side of the inner cavity forming body, and the flow control valve is formed on an annular valve support body, and the annular valve support body is embedded in the circular cylindrical inner cavity, and the integral displacement body is formed into a solid rod or cylindrical shape that is embedded in the inner cavity forming body in a slidable manner.

[0030] Thus, in the damper of the present invention, since the inner cavity is formed inside the inner cavity forming body, the integral displacement body itself can be formed into a solid rod or cylinder, thereby making it possible to provide a variety of arrangement options for the damper.

[0031] Alternatively, a steering device may be provided, specifically comprising: a steering shaft extending into a rod-like shape and rotating in response to steering wheel operation; a rack bar extending into a rod-like shape and transmitting the steering shaft's rotational motion into axially reciprocating motion; an intermediate connecting body connected to each of the two ends of the rack bar, directly or indirectly connected to wheels to be steered; and a rack housing covering the rack bar. The steering device may include the damper according to any one of claims 9 to 12, the damper being disposed between the rack housing and the rack bar or the intermediate connecting body to absorb impact from the wheels. Thus, the steering device of the present invention can achieve the same effects as the aforementioned flow control valve and damper.

[0032] In this case, the steering device may include the damper according to claim 11, wherein the inner cavity forming body is formed in the intermediate connecting body, and the integral displacement body is formed in a position where the rack housing is contacted or separated by the reciprocating motion of the rack rod.

[0033] Thus, the steering system of the present invention has an inner cavity-forming body formed within an intermediate connecting body, such as a tie rod or rack ball joint mechanism, and an integral displacement body formed within the inner cavity-forming body at a location where the reciprocating motion of the rack rod causes the damper to contact or separate from the rack housing. In other words, the steering system of the present invention facilitates maintenance and replacement of the damper because the damper is located within an intermediate connecting body, such as a tie rod or rack ball joint mechanism.

[0034] In addition, in this case, on the basis of the above-mentioned steering device, a damper as described in technical solution 12 can be provided, wherein the inner cavity forming body is formed at the end of the rack housing, and the integral displacement body has a rack rod or an intermediate connecting body passing through it, and is formed at a position where it contacts or separates from the rack rod or the intermediate connecting body through the reciprocating motion of the rack rod.

[0035] Thus, the steering system of the present invention has an inner cavity-forming body formed at the end of the rack housing, and a rack rod or an intermediate connecting member (such as a tie rod or rack ball joint mechanism) extends through the interior of the integral displacement body. The integral displacement body is formed at a position where it contacts and separates from the rack rod or tie rod due to the reciprocating motion of the rack rod. As a result, the steering system of the present invention can reduce the weight of intermediate connecting members such as the tie rod or rack ball joint mechanism by installing the damper in the rack housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is an explanatory diagram schematically showing the outline of the overall structure of the steering device according to the first embodiment of the present invention.

[0037] Figure 2 It means composition Figure 1 The schematic perspective view of the external structure of the damper of the steering device according to the first embodiment of the present invention is shown.

[0038] Figure 3 Yes Figure 2 A cross-sectional view schematically showing the internal structure of the damper.

[0039] Figure 4 It means from Figure 3 A cross-sectional view of the integral displacement body and the socket body as viewed along line 4-4 is shown.

[0040] Figure 5 It is expressed in detail in Figure 3 The diagram shows an enlarged partial view of the structure within the dotted circle 5 in the damper.

[0041] Figure 6 It means in Figure 3 The figure shows a cross-sectional view of the damper at the moment when the integral displacement body contacts the rack housing.

[0042] Figure 7 It shows that Figure 5 A partially enlarged view of the damper showing a state in which the first flow control valve allows fluid to flow.

[0043] Figure 8 It shows that Figure 5 A partially enlarged view of the damper showing a state where the first flow control valve does not allow fluid to flow.

[0044] Figure 9 It is a cross-sectional view schematically showing the internal structure of a damper according to a second embodiment of the present invention.

[0045] Figure 10 It only means from Figure 9 The front view of the flow control valve as viewed from line 10-10 is shown.

[0046] Figure 11 It means in Figure 9 The cross-sectional view shows the state of the socket body and the integral displacement body in the damper at the moment of contact.

[0047] Figure 12 It is aimed at Figure 9 The portion indicated by the dotted circle 12 in the damper is a partially enlarged view showing a state in which the first flow control valve allows the fluid to flow.

[0048] Figure 13 It shows that Figure 9 A partially enlarged view of the damper showing a state where the first flow control valve does not allow fluid to flow.

[0049] Figure 14 This is a partially enlarged view showing a state in which both the first flow hole and the second flow hole are completely blocked and the first flow control valve does not allow the fluid to flow in the damper according to a modified example of the present invention.

[0050] Figure 15 This is a partially enlarged view showing a state in which a portion of the first flow hole and a portion of the second flow hole overlap with each other to ensure the flow of the fluid in a damper according to another modified example of the present invention.

[0051] Figure 16 This is a partially enlarged view showing a state in which only the second flow hole is completely blocked and the first flow control valve does not allow the fluid to flow in a damper according to another modified example of the present invention.

[0052] Figure 17 This is a partially enlarged view showing a state in which only the first flow hole is completely blocked and the first flow control valve does not allow the fluid to flow in the damper according to a modified example of the present invention.

[0053] Figure 18 Yes Figure 17A partially enlarged perspective view of the appearance structure of the front end portion of the second flow body is shown. DETAILED DESCRIPTION

[0054] <First embodiment>

[0055] Hereinafter, a first embodiment of a steering device including a flow control valve and a damper according to the present invention will be described with reference to the drawings. Figure 1 : is an explanatory diagram schematically showing the outline of the overall structure of the steering device 100 according to the first embodiment of the present invention. Figure 2 It means composition Figure 1 1 is a perspective view schematically showing the external structure of the damper 120 of the first embodiment of the present invention in the steering device 100. Figure 3 Yes Figure 2 The schematic cross-sectional view of the internal structure of the damper 120 is shown. Figure 4 It means from Figure 3 The cross-sectional view of the integral displacement body 130 and the socket body 107 as viewed along line 4-4 is shown. Figure 5 It is expressed in detail in Figure 3 The structure within the dashed circle 5 of the damper 120 is shown in a partially enlarged view.

[0056] The steering device 100 is a mechanical device for steering two front wheels (or rear wheels) of a four-wheeled self-propelled vehicle (not shown) in left and right directions.

[0057] (Structure of Steering Device 100)

[0058] The steering device 100 includes a steering wheel 101. The steering wheel 101 is an operating member (i.e., a handle) for the driver of the self-propelled vehicle to manually control the direction of travel, and is formed by forming a resin material or a metal material into an annular shape. A steering shaft 102 is connected to the steering wheel 101.

[0059] The steering shaft 102 is a rod-shaped component that rotates about its axis in response to clockwise or counterclockwise rotation of the steering wheel 101. It is composed of one or more metal rods connected via a universal joint, etc. The steering shaft 102 is connected to the steering wheel 101 at one end, and has a pinion 102a formed at the other end, which is connected to the rack bar 103.

[0060] The rack bar 103 is a rod-shaped component that moves back and forth along its axis, transmitting the steering force and steering amount applied to each of the two wheels 112 to the knuckle arm 111. It is made of metal. In this case, a rack gear 103a is formed in a portion of the rack bar 103, which engages with the pinion 102a of the steering shaft 102. In other words, the pinion 102a and rack gear 103a form a rack-and-pinion mechanism (steering gearbox) that converts the rotational motion of the steering shaft 102 into the reciprocating linear motion of the rack bar 103.

[0061] The two axial ends of the rack bar 103 are exposed from the rack housing 104 when the rack and pinion mechanism is covered by the rack housing 104. The two ends of the rack bar 103 exposed from the rack housing 104 are connected to wheels 112 via an intermediate connector 105 and a knuckle arm 111.

[0062] The rack housing 104 is a member for covering and protecting the main parts such as the rack and pinion mechanism in the rack bar 103 and is formed of a metal material in a cylindrical shape. The rack housing 104 is fixedly mounted on a chassis (not shown) of the self-propelled vehicle.

[0063] The intermediate connector 105 is a component for transmitting the steering force and steering amount transmitted from the rack bar 103 to the knuckle arm 111. It is mainly composed of a rack ball joint mechanism 106 and a tie rod 110. The rack ball joint mechanism 106 is a component that movably connects the front end of the tie rod 110 to the rack bar 103 and forms the damper 120. It is mainly composed of a socket body 107 and a stud body 108.

[0064] The socket body 107 is a component that movably connects the stud body 108 to the front end of the rack rod 103 and forms the damper 120. It is made of a metal material formed into a round rod shape. The socket body 107 has a ball retaining portion 107a formed at one end (the right side in the figure) and an externally threaded portion 107b formed on the other end (the left side in the figure) that screws into the front end of the rack rod 103. The ball retaining portion 107a is formed into a concave spherical shape so that it can slidably fit and retain the ball portion 108a of the stud body 108. Furthermore, the damper 120 is formed between the ball retaining portion 107a and the externally threaded portion 107b in the socket body 107.

[0065] The stud body 108 is a component used to movably connect the tie rod 110 to the socket body 107. It is formed of a metal material formed into a round rod shape. The stud body 108 has a spherical ball portion 108a formed at one end (the left side in the figure) and an external thread portion (not shown) formed on the other end (the right side in the figure) to be screwed into the end of the tie rod 110.

[0066] Tie rod 110 is a component that movably connects knuckle arm 111 to the front end of rack ball joint mechanism 106. A ball joint is movably mounted on the front end of a rod-shaped tie rod body. Knuckle arm 111 is a metal component that holds wheel 112 relative to tie rod 110 and transmits the steering force and steering amount transmitted from tie rod 110 to wheel 112. It is formed in the shape of multiple rod-shaped members extending from the periphery of a cylindrical portion. Wheels 112 are a pair of left and right components that rotate on the road surface to move the self-propelled vehicle forward or backward. Rubber tires are mounted on the outer sides of the metal wheels.

[0067] The damper 120 is a device for absorbing a strong pressing force (impact) transmitted from the wheel 112 and is formed in each of the left and right intermediate connecting bodies, more specifically, in each of the left and right socket bodies 107. The damper 120 includes an inner cavity 121.

[0068] The inner cavity 121 is a portion that fluid-tightly contains the fluid 124. It is formed into a circular cylindrical shape that is cut into a concave shape along the circumferential direction on the outer periphery of the socket body 107 and extends in the axial direction. In other words, the socket body 107 corresponds to the inner cavity forming body of the present invention. In this embodiment, the bottom of the inner cavity 121 and the end on one side of the axial direction of the socket body 107 (the right side in the figure) are respectively formed by the socket body 107 itself, and the other end on the axial direction (the left side in the figure) is formed by the wall forming body 122. In addition, the outer side of the inner cavity 121 is covered by the integral displacement body 130.

[0069] The wall-forming member 122 is a component that forms the wall portion (left side in the figure) of the inner cavity 121. It is formed by forming a metal material into a circular ring shape. This wall-forming member 122 is screwed onto the outer peripheral surface of the socket body 107 on the other axial side (left side in the figure), becoming integral with the socket body 107. Furthermore, cushioning materials 123a and 123b, each made of an elastic material such as polyurethane resin, are provided at both axial ends of the socket body 107 in the inner cavity 121. In this case, cushioning material 123a is formed to be thicker than cushioning material 123b.

[0070] The fluid 124 is a substance that allows the damper 120 to function as a damper by imparting resistance to the flow control valve 140 that slides in the inner cavity 121, and is filled in the inner cavity 121. The fluid 124 is composed of a liquid, gel, or semi-solid substance with a viscosity that corresponds to the specifications of the damper 120. In this case, the viscosity of the fluid 124 is appropriately selected according to the specifications of the damper 120. In this embodiment, the fluid 124 is composed of oil, such as mineral oil or silicone oil. In addition, the fluid 124 is Figure 3 and Figure 5 Indicated by the hatched line in the dotted circle ( Figure 9 、 Figures 12 to 15 Same).

[0071] Furthermore, sliding bushings 125a and 125b are respectively embedded in the outer circumferential surfaces of the socket body 107 and the wall-forming body 122 on both sides of the socket body 107 in the axial direction of the inner cavity 121. The sliding bushings 125a and 125b are components for allowing the integral displacement body 130 to slide back and forth smoothly along the axial direction of the socket body 107. They are formed of a metal material into an annular shape with an outer diameter slightly larger than that of the socket body 107.

[0072] Seal rings 126a and 126b, each made of an elastomeric material such as rubber, are embedded in the outer peripheral surfaces of the socket body 107 and the wall-forming body 122 on the side opposite the inner cavity 121 from the sliding bushings 125a and 125b. These seal rings 126a and 126b prevent the fluid 124 in the inner cavity 121 from leaking out when the integral displacing body 130 slides relative to the socket body 107.

[0073] The integral displacement body 130 covers the radially outer side of the inner cavity 121 and forms the flow control valve 140. It is formed by forming a metal material into a cylindrical shape. Specifically, the integral displacement body 130 is formed into a cylindrical shape that slidably fits onto the outer circumferential surface of the socket body 107. In this case, the integral displacement body 130 is formed to a length that protrudes from the end of the socket body 107 on the rack housing 104 side.

[0074] A flow control valve 140 is formed in a protruding shape at the axial center of the inner periphery of the integral displaceable body 130. An elastic retaining portion 131 is formed between the flow control valve 140 and the inner periphery of the integral displaceable body 130. Furthermore, a dust cover 133 and a dust seal 134 are provided at both axial ends of the inner periphery of the integral displaceable body 130.

[0075] The elastic member retaining portion 131 houses one of the two ends of the resetting elastic member 132 and is formed into a circular ring between the inner circumference of the integral displacement body 130 and the flow control valve 140. The resetting elastic member 132 is a component used to elastically press the flow control valve 140 toward the left end (as shown) within the inner cavity 121 and is composed of a metal coil spring. One end (the left end) of the resetting elastic member 132 is housed within the elastic member retaining portion 131, elastically pressing the integral displacement body 130. The other end (the right end) elastically presses the outer circumference of the socket body 107 via the sliding bushing 125a.

[0076] The dust cover 133 is a component for preventing dust from entering the interior of the integral displacement body 130 from one of the two ends of the integral displacement body 130 (the left side in the figure), that is, the rack housing 104 side. It is formed of an elastic material such as rubber material into a cylindrical shape. One end of the dust cover 133 is connected to the end of the integral displacement body 130, and the other end is connected to the wall forming body 122. In addition, Figure 2 In the figure, the dust cover 133 is omitted.

[0077] Like the dust cover 133, the dust seal 134 is a component used to prevent dust from entering the interior of the integral displacing body 130 from the other (right side in the figure) of the two ends of the integral displacing body 130, namely, the stud body 108 side. It is formed of an elastic material such as rubber formed into an annular shape. The dust seal 134 is embedded in an annular groove cut into the end of the integral displacing body 130.

[0078] An accumulator housing portion 135 is formed on the outer periphery of the integrally movable body 130. This cylindrical portion is used to fluid-tightly house the accumulator 136. It protrudes from the outer periphery of the integrally movable body 130 and extends along the longitudinal direction of the integrally movable body 130. One end of the accumulator housing portion 135 communicates with the first flow body 153 side of the inner cavity 121, while the other end is sealed by a plug.

[0079] The accumulator 136 compensates for volume changes caused by expansion or contraction of the fluid 124 in the inner cavity 121 due to temperature changes. The accumulator 136 houses a piston that reciprocates in the accumulator housing 135 and is elastically pressed toward the inner cavity 121 by a coil spring.

[0080] The flow control valve 140 is a device for controlling the flow of the fluid 124 within the inner chamber 121 by restricting the flow of the fluid 124 and thereby generating a damping force in the damper 120. The flow control valve 140 mainly includes a valve support 141, a first flow control valve 150, a second flow control valve 160, and a third flow control valve 170.

[0081] The valve support body 141 forms the first flow control valve 150, the second flow control valve 160, and the third flow control valve 170, respectively. It is formed into a flat, annular shape that protrudes inward from the inner periphery of the integral displacement body 130. The inner periphery of the valve support body 141 is formed into a smooth cylindrical surface to slide fluid-tightly against the bottom of the inner cavity 121, and a sealing ring 142 composed of an elastomer is embedded therein.

[0082] The first flow control valve 150 functions as a trigger for generating the maximum damping force when a strong impact force acts on the damper 120. It primarily comprises a second flow body housing 151, a first flow body 153, a second flow body 156, and a separating elastic body 159. The second flow body housing 151 slidably houses the second flow body 156, described later, and is formed in the shape of a bottomed cylinder with an open end at one end (the right side in the figure) of the valve support body 141.

[0083] In this case, the second flow body housing portion 151 is formed so that the side surface on the front side of the valve support body 141, whichever is the side facing forward, remains open when the integral displacement body 130 slides relative to the socket body 107 against the elastic force of the return spring 132. A retaining ring 152 is embedded in an annular groove formed on the inner circumference of the second flow body housing portion 151 near the opening. The retaining ring 152 is a component used to prevent the second flow body 156 housed in the second flow body housing portion 151 from falling out. It is formed of a metal material in the form of a C-shaped ring.

[0084] The first flow body 153 is a portion for controlling the flow of the fluid 124 in cooperation with the second flow body 156, and primarily comprises a first flow hole 154 and a first aperture limiting portion 155. The first flow hole 154 is a through-hole for allowing the fluid 124 to flow, and is formed at the bottom of the second flow body housing 151. In this case, the first flow hole 154 is formed at the edge of the bottom, which is eccentric with respect to the centerline of the second flow body housing 151. That is, one side of the inner cavity 121 of the second flow body housing 151 (the side with the buffer material 123a) has a larger opening, while the other side (the side with the buffer material 123b) has a smaller opening due to the first flow hole 154.

[0085] The first aperture restrictor 155 blocks the flow of the fluid 124 in the second flow hole 157 and is formed in a wall-like shape around the first flow hole 154. Furthermore, the first aperture restrictor 155 is formed at a position opposite the second flow hole 157 so as to completely block the second flow hole 157 of the second flow body 156 when the second flow body 156 is in contact with the first flow body 153. In this embodiment, the first aperture restrictor 155 is formed by the bottom of the second flow body housing 151.

[0086] The second flow body 156 is a component used to control the flow of the fluid 124 in conjunction with the first flow body 153. It is formed by forming a metal material into a cylindrical shape. In this case, the second flow body 156 consists of a large-diameter portion 156a that slides relative to the inner circumference of the second flow body housing 151, and a small-diameter portion 156b with a smaller diameter than the large-diameter portion 156a. Furthermore, the second flow body 156 is formed with a second flow hole 157 and a second aperture restriction 158.

[0087] The second flow hole 157 is a through-hole for circulating the fluid 124. It is composed of a large-diameter hole 157a and a small-diameter hole 157b that penetrate the second flow body 156. The large-diameter hole 157a is formed in the second flow body 156 so as to open on the side surface on the front side when the integral displaceable body 130 slides against the elastic force of the return elastic body 132. The small-diameter hole 157b extends from the innermost portion of the large-diameter hole 157a to the side surface on the rear side when the integral displaceable body 130 slides against the elastic force of the return elastic body 132.

[0088] In this case, a flat, annular step 157c is formed between the large-diameter hole 157a and the small-diameter hole 157b. Furthermore, the end of the small-diameter hole 157b on the large-diameter hole 157a side is formed with a tapered portion 157d, whose diameter tapers continuously toward the inside of the small-diameter hole 157b. Furthermore, the small-diameter hole 157b is positioned and sized to communicate with the large-diameter hole 157a and to face the first aperture restrictor 155, rather than the first flow hole 154. In other words, the small-diameter hole 157b is positioned and sized on the first aperture restrictor 155 so as not to overlap with the first flow hole 154. In this embodiment, the small-diameter hole 157b is concentric with the second flow body 156 and the large-diameter hole 157a and has a smaller diameter than the first flow hole 154.

[0089] The second aperture restrictor 158 blocks the flow of the fluid 124 in the first flow hole 154 and is formed as a wall around the small-diameter hole 157b that constitutes the second flow hole 157. Specifically, the second aperture restrictor 158 is formed opposite the first flow hole 154 so that it blocks a portion of the first flow hole 154 of the first flow body 153 when the second flow body 156 contacts the first flow body 153. In this embodiment, the second aperture restrictor 158 is formed as a flat ring having a size of approximately one-third of the first flow hole 154 of the first flow body 153 when the second flow body 156 contacts the first flow body 153.

[0090] The separating elastic body 159 is a component that exerts an elastic force within the second flow body housing 151 to separate the second flow body 156 from the first flow body 153. It is composed of a metal coil spring. One end of the separating elastic body 159 (left side in the figure) presses against the first aperture limiting portion 155 (the bottom of the second flow body housing 151), while the other end (right side in the figure) engages with the outer periphery of the small-diameter portion 156b. The elastic force of the separating elastic body 159 is set to a strength corresponding to the magnitude of the external force that the damper 120 is intended to generate the maximum damping force. The first flow control valve 150 is provided in one valve support body 141.

[0091] The second flow control valve 160 is a valve that prevents the flow of fluid 124 from the front to the rear of the sliding displacement when the integral displacement body 130 slides relative to the socket body 107, overcoming the elastic force of the return elastic body 132. However, when the integral displacement body 130 slides due to the elastic force of the return elastic body 132, it facilitates the flow of fluid 124 from the front to the rear of the sliding displacement. Specifically, the second flow control valve 160 is comprised of a one-way valve. The structure of the one-way valve constituting the second flow control valve 160 is well known, and therefore a detailed description thereof will be omitted. The second flow control valve 160 is provided in the valve support body 141 at a position 180° circumferentially relative to the first flow control valve 150.

[0092] The third flow control valve 170 is a valve that restricts the flow of the fluid 124, allowing it to circulate, when the integral displacement body 130 slides relative to the socket body 107 against the elastic force of the return elastic body 132, and when the integral displacement body 130 slides relative to the socket body 107 due to the elastic force of the return elastic body 132. This third flow control valve 170 is formed by a through-hole formed in the valve support body 141. In this embodiment, the third flow control valve 170 is formed at two intermediate positions between the first flow control valve 150 and the second flow control valve 160 on the circumference of the valve support body 141. Furthermore, this third flow control valve 170 serves as the flow restriction valve of the present invention.

[0093] (Operation of Steering Device 100)

[0094] Next, the operation of the steering system 100 configured as described above will be described. The steering system 100 is incorporated into a four-wheeled self-propelled vehicle (not shown) as a mechanism for steering the steering wheels (e.g., the two front wheels) in the left and right directions. Furthermore, the steering system 100 changes the directions of the two wheels 112 in response to the driver's operation of the steering wheel 101, thereby determining the vehicle's travel direction.

[0095] During operation of this self-propelled vehicle, when the rack bar 103 is displaced to near its left or right displacement limit relative to the pinion 102a, the damper 120 in the steering system 100 comes into play. In this case, the rack bar 103's displacement limit refers to the left or right steering control limit of the wheels 112. In addition to situations where the driver of the self-propelled vehicle turns the steering wheel 101 clockwise or counterclockwise to near its rotation limit, there are also situations where a wheel 112 collides with an obstacle such as a curb, causing a large input to act on the rack bar 103 from the wheel 112 side.

[0096] First, the case where the damper 120 is not working will be described. Figure 3As shown, when the rack bar 103 is within a range close to its displacement limit, such as when the wheels 112 of the self-propelled vehicle are not steered to near the steering limit, the integral displacement body 130 does not collide with the rack housing 104, and thus the damper 120 does not operate. Figure 5 As shown, the flow control valve 140 of the damper 120 is pressed against the wall forming body 122 via the buffer material 123b in the inner cavity 121 by the elastic force of the return elastic body 132. That is, the integral displacement body 130 is maintained in a state where it is elastically positioned on the socket body 107 at the position closest to the rack housing 104.

[0097] Furthermore, the first flow control valve 150 maintains the second flow body 156 positioned farthest from the first flow body 153 by the elastic force of the separation elastic body 159. That is, the first flow control valve 150 is in a state where the flow of the fluid 124 is possible.

[0098] Next, the operation of the damper 120 will be described. Figure 6 As shown, when the rack bar 103 reaches its displacement limit (see the dashed arrow), such as when the wheels 112 of the self-propelled vehicle are steered near their steering limits, the end of the integral displacement body 130 contacts the rack housing 104, and the damper 120 begins to operate. In this case, during the operation of the damper 120, the end of the integral displacement body 130 may contact the rack housing 104 with a relatively weak force or with a relatively strong force.

[0099] First, when the end of the integral displacement body 130 contacts the rack housing 104 with a relatively weak force (low speed), as shown in FIG. Figure 7 As shown, the integral displacement body 130 slowly slides relative to the socket body 107 toward the stud body 108 (see the dotted arrow). Specifically, the flow control valve 140 displaces toward the cushioning material 123a within the inner cavity 121, overcoming the elastic force of the return elastic body 132. In this situation, the fluid 124 in the first flow control valve 150 flows from the large-diameter hole 157a of the second flow hole 157 of the second flow body 156 toward the small-diameter hole 157b.

[0100] However, in this case, since the flow control valve 140 slowly displaces within the inner cavity 121, the force pressing the second flow body 156 is smaller than the elastic force of the separation elastic body 159. Therefore, the second flow body 156 does not displace toward the first flow body 153 and is pressed against the first flow body 153. Therefore, in the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows through the second flow hole 157 of the second flow body 156 and the first flow hole 154 of the first flow body 153, respectively, toward the rear side in the displacement direction with slight flow resistance (see the dotted arrows).

[0101] Furthermore, the second flow control valve 160 is a one-way valve that prevents the flow of the fluid 124 from the front side to the rear side in the displacement direction of the flow control valve 140 when the integral displacement body 130 overcomes the elastic force of the return elastic body 132 and slides and displaces. Therefore, no flow of the fluid 124 occurs. Furthermore, the third flow control valve 170 is a valve that allows the flow of the fluid 124 in both the front and rear directions in the displacement direction of the flow control valve 140. Therefore, the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 140 with minimal flow resistance.

[0102] Therefore, the flow control valve 140 is displaced toward the cushioning material 123 a while generating a negligibly small damping force.

[0103] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the end of the integral displacement body 130 is separated from the rack housing 104, the integral displacement body 130 is displaced to its original position by the elastic force of the return elastic body 132 (see FIG. Figure 5 In this case, in the first flow control valve 150 , the fluid 124 flows from the first flow body 153 side and flows toward the second flow body 156 side.

[0104] In this case, the second flow body 156 is located at its original position farthest from the first flow body 153 due to the elastic force of the separation elastic body 159 and the pressing force of the fluid 124 flowing from the first flow body 153. Therefore, with respect to the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows toward the rear side in the displacement direction with slight flow resistance through the first flow hole 154 of the first flow body 153 and the second flow hole 157 of the second flow body 156.

[0105] Furthermore, the second flow control valve 160 is a one-way valve that allows the fluid 124 to flow from the front side to the rear side in the displacement direction of the flow control valve 140 when the integral displacement body 130 is slidably displaced by the elastic force of the return elastic body 132. Therefore, the fluid 124 flows with minimal flow resistance. Furthermore, the third flow control valve 170 is a valve that allows the fluid 124 to flow in both the front and rear directions in the displacement direction of the flow control valve 140. Therefore, the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 140 with minimal flow resistance.

[0106] Therefore, the flow control valve 140 is displaced toward the cushioning material 123b while generating a negligibly small damping force. As a result, the integral displaceable body 130 is slidably displaced toward the rack housing 104 at a faster displacement speed than before.

[0107] Next, when the end of the integral displacement body 130 contacts the rack housing 104 with a strong force (at high speed) (e.g., due to a sudden steering motion by the driver or a collision of the wheel 112 with a curb), the integral displacement body 130 rapidly slides toward the stud body 108 relative to the socket body 107. Specifically, the flow control valve 140 rapidly displaces toward the cushioning material 123a within the inner cavity 121, overcoming the elastic force of the return elastic body 132.

[0108] In this case, if Figure 8 As shown, the force of the fluid 124 pressing the second flow body 156 is greater than the elastic force of the separation elastic body 159, so the first flow control valve 150 is displaced toward the first flow body 153 and pressed against the first flow body 153. In this case, after the second flow body 156 begins to displace toward the first flow body 153 due to the pressing force of the fluid 124 acting on the step portion 157c and the tapered portion 157d of the small-diameter hole 157b, the pressing force of the fluid 124 also acts on the end of the large-diameter hole 157a, causing it to displace toward the first flow body 153.

[0109] Furthermore, in this case, the first aperture restricting portion 155 and the second aperture restricting portion 158 are formed at positions opposing the second flow hole 157 and the first flow hole 154, respectively, thereby blocking all of the second flow hole 157 and a portion of the first flow hole 154. Therefore, in the first flow control valve 150, when the flow control valve 140 is displaced toward the stud body 108, the fluid 124 does not flow (see the dashed arrow). Similarly, in this case, the second flow control valve 160 does not flow the fluid 124, as described above.

[0110] Furthermore, the third flow control valve 170 alone among the flow control valves 140 allows the flow of fluid 124, thus generating a significant flow resistance. Consequently, the flow control valve 140 overcomes this significant flow resistance and displaces toward the cushioning material 123a. This causes the integral displacement body 130 to slide toward the stud body 108, generating a significant damping force. In other words, the damper 120 can dampen the strong impact generated by the rack bar 103.

[0111] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the end portion of the integral displacement body 130 is separated from the rack housing 104, the integral displacement body 130 is displaced to its original position by the elastic force of the return elastic body 132 in the same manner as described above (see FIG. Figure 5 That is, the integral displaceable body 130 is displaced toward the cushioning material 123 b by generating a negligibly small damping force through the flow control valve 140 , and is rapidly slidably displaced toward the rack housing 104 .

[0112] Furthermore, the second flow body 156 is separated from the first flow body 153 by the elastic force of the separation elastic body 159 and the pressing force of the fluid 124 flowing from the first flow body 153, returning to its original position. In this case, since the second aperture restricting portion 158 is formed at a position opposing a portion of the first flow hole 154, the second flow body 156 can guide a portion of the fluid 124 flowing from the first flow hole 154 into the second flow body accommodating portion 151 toward the second flow hole 157. Furthermore, in the first flow control valve 150, as described above, the fluid 124 on the forward side in the displacement direction flows through the first flow hole 154 of the first flow body 153 and the second flow hole 157 of the second flow body 156, respectively, toward the rearward side in the displacement direction with minimal flow resistance.

[0113] As can be understood from the above description of the operating method, according to the first embodiment, the damper 120 is configured such that a first flow body 153 and a second flow body 156, each having a first flow hole 154 and a second flow hole 157 through which the fluid 124 flows, are elastically in close contact with or separated from each other, and the first aperture restriction 155 is configured to entirely block the second flow hole 157. Thus, the damper 120 of the above embodiment can constitute the steering device 100. When a large external force acts between the first flow body 153 and the second flow body 156, the first flow hole 154 and the second flow hole 157 are blocked by the second aperture restriction 158 and the first aperture restriction 155, thereby restricting the flow of the fluid 124. This can thereby attenuate the large external force and absorb a large impact force.

[0114] <Second embodiment>

[0115] Next, refer to Figures 9 to 13 A second embodiment of a steering system including a flow control valve and a damper according to the present invention will be described. The steering system 200 in this second embodiment differs from the first embodiment in that a damper 210, equivalent to the damper 120 in the first embodiment, is assembled to the rack housing 104 rather than the socket body 107. Therefore, the description of the steering system 200 in this second embodiment will focus on the parts that differ from the steering system 100 in the first embodiment, while descriptions of common or corresponding parts between the two embodiments will be omitted as appropriate. Furthermore, in the description of this second embodiment, components identical to those in the first embodiment are denoted by the same reference numerals as in the first embodiment.

[0116] (Structure of Steering Device 200)

[0117] The steering device 200 has a cylindrical damper 210 mounted on the front end of the cylindrical rack housing 104, and a dust cover 201 mounted to cover the damper 210. The dust cover 201 is a member for preventing the damper 210 from being contaminated and is formed by forming an elastic material such as rubber into a cylindrical shape.

[0118] The rack rod 103 extends through the interior of a cylindrical damper 210 mounted on the front end of the rack housing 104. Furthermore, a rack ball joint mechanism 106 is mounted on the front end of the rack rod 103. In this case, the socket body 107 mounted on the rack rod 103 is formed so that its outer periphery protrudes from the outer periphery of the rack rod 103 in a flange-like shape and is positioned opposite the end of the integral displacement body 230.

[0119] The damper 210 includes an inner cavity forming body 211. This inner cavity forming body 211 is a component used to form an inner cavity 217 and to attach the damper 210 to the rack housing 104. It is formed by forming a metal material into a cylindrical shape. Specifically, the inner cavity forming body 211 corresponds to the socket body 107 described in the first embodiment. An externally threaded portion 211a for threaded engagement with the rack housing 104 is formed on one end (the left side in the figure) of the outer periphery of the inner cavity forming body 211. An oil supply port 212 and an accumulator housing 213 are formed on the other end (the right side in the figure).

[0120] The oil supply port 212 is a flow path for injecting and discharging the fluid 124 into the inner cavity 217 and is openably and closably sealed by a plug. The accumulator housing 213 and the accumulator 214 correspond to the accumulator housing 135 and the accumulator 136 in the first embodiment, respectively. Furthermore, the inner cavity-forming body 211 has wall-forming bodies 215 and 216 threadedly engaged at both ends, forming a cylindrical inner cavity 217 between these two wall-forming bodies 215 and 216.

[0121] Wall-forming bodies 215 and 216 form the left and right walls of inner cavity 217 (as shown). They are formed from a metal material formed into an annular shape. Specifically, wall-forming bodies 215 and 216 correspond to wall-forming body 122 in the first embodiment described above. Therefore, inner cavity 217 is formed into an annular cylindrical shape, extending axially inside inner cavity-forming body 211 and between the integral displacement body 230 (described later). Of these wall-forming bodies 215 and 216, wall-forming body 216 on the side of intermediate connecting body 105 has a restoring elastic body 218 embedded in its outer periphery.

[0122] The resilient return element 218 is a component used to elastically press the flow control valve 240 against the right end portion (as shown) within the inner cavity 217. It is comprised of a metal coil spring. Specifically, the resilient return element 218 corresponds to the resilient return element 132 in the first embodiment described above. One end portion (the left side as shown) of the resilient return element 218 elastically presses the wall-forming body 216, while the other end portion (the right side as shown) elastically presses the integral displacement body 230 via a support plate 218a.

[0123] In addition, the wall forming bodies 215 and 216 are respectively provided with cushioning materials 221a and 221b, sliding bushings 222a and 222b, sealing rings 223a and 223b and dustproof seals 224a and 224b corresponding to the cushioning materials 123a and 123b, sliding bushings 125a and 125b, sealing rings 126a and 126b and dustproof seals 134 in the above-mentioned first embodiment.

[0124] The integral displacement body 230 covers the radially inner side of the inner cavity 217 and forms the flow control valve 240. It is constructed by forming a metal material into a cylindrical shape. Specifically, the integral displacement body 230 corresponds to the integral displacement body 130 described in the first embodiment. This integral displacement body 230 is formed into a cylindrical shape that slidably fits onto the inner circumferential surfaces of the wall-forming bodies 215 and 216 via sliding bushings 222a and 222b. In this case, the integral displacement body 230 is formed to a length that protrudes from each end of the wall-forming bodies 215 and 216. Furthermore, the inner diameter of the integral displacement body 230 is sized to allow the rack bar 103 to pass through.

[0125] The support plate 218a is fixedly mounted on one end (the right side in the figure) of the outer periphery of the integral displacement body 230. A fixed sleeve 231 and a flow control valve 240 are mounted from the other end (the left side in the figure) to the axial center. The fixed sleeve 231 is a component used to press and secure the flow control valve 240, which fits in the small-diameter portion formed on the outer periphery of the integral displacement body 230, against the large-diameter portion formed on the outer periphery of the integral displacement body 230. It is formed of a cylindrical metal material. The fixed sleeve 231 is fitted into the outer periphery of the integral displacement body 230, forming an integral assembly. It slides relative to the wall-forming body 215 via a sliding bushing 222a.

[0126] The flow control valve 240 is a device for controlling the flow of the fluid 124 within the inner cavity 217 by restricting the flow of the fluid 124 and thereby generating a damping force in the damper 210. This valve corresponds to the flow control valve 140 in the first embodiment described above. The flow control valve 240 mainly includes a valve support 241, a first flow control valve 150, a second flow control valve 160, and a third flow control valve 170.

[0127] The valve support body 241 is a component that forms the first flow control valve 150, the second flow control valve 160, and the third flow control valve 170. It is formed by forming a metal material into a flat circular ring shape. Specifically, the valve support body 241 is formed separately from the integral displacement body 230 and is integrally attached to the integral displacement body 230 via a fixing sleeve 231. A sealing ring 242, corresponding to the sealing ring 142 in the first embodiment, is embedded in the outer periphery of the valve support body 241.

[0128] The first flow control valve 150, the second flow control valve 160, and the third flow control valve 170 are configured similarly to those in the above-described embodiment, and therefore their description will be omitted. Furthermore, the flow control valve 240 is mounted on the outer periphery of the integral displacement body 230 with the large-diameter portion 156a of the second flow body 156 of the first flow control valve 150 opening toward the buffer material 221a (left side in the figure).

[0129] (Operation of Steering Device 200)

[0130] Next, the operation of the steering device 200 thus configured will be described. Similar to the steering device 100 in the above embodiment, the steering device 200 activates the damper 210 when the rack bar 103 is displaced near the left and right displacement limit relative to the pinion 102a.

[0131] Specifically, when the rack bar 103 is within a range close to the displacement limit, such as when the wheel 112 of the self-propelled vehicle is not steered to the limit of the steering, the socket body 107 does not collide with the integral displacement body 230, and thus the damper 210 does not operate (see FIG. Figure 9 In this case, the flow control valve 240 of the damper 210 is pressed against the wall forming body 216 via the buffer material 221b within the inner cavity 217 by the elastic force of the return elastic body 218. In other words, the integral displaceable body 230 is maintained in a state where it is elastically positioned closest to the socket body 107 within the inner cavity 217.

[0132] Furthermore, the first flow control valve 150 maintains the second flow body 156 positioned farthest from the first flow body 153 by the elastic force of the separation elastic body 159. That is, the first flow control valve 150 is in a state where the flow of the fluid 124 is possible.

[0133] Next, if Figure 11 As shown, when the rack bar 103 reaches near its displacement limit, such as when the wheel 112 of the self-propelled vehicle is steered near its steering limit, the socket body 107 contacts the end of the integral displacement body 230 and the damper 210 starts to operate.

[0134] First, when the socket body 107 contacts the end of the integral displacement body 230 with a relatively weak force (low speed), as shown in FIG. Figure 12 As shown, the integral displacement body 230 slowly slides relative to the inner cavity forming body 211 toward the rack housing 104. Specifically, the flow control valve 240 displaces toward the cushioning material 221a (left side in the figure) within the inner cavity 217, overcoming the elastic force of the return elastic body 218. In this situation, the fluid 124 in the first flow control valve 150 flows from the large-diameter hole 157a side of the second flow hole 157 of the second flow body 156 toward the small-diameter hole 157b side.

[0135] However, in this case, since the flow control valve 240 slowly displaces within the inner cavity 217, the force pressing the second flow body 156 is smaller than the elastic force of the separation elastic body 159. Therefore, the second flow body 156 does not displace toward the first flow body 153 and is pressed against the first flow body 153. Therefore, in the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows through the second flow hole 157 of the second flow body 156 and the first flow hole 154 of the first flow body 153, respectively, toward the rear side in the displacement direction with slight flow resistance.

[0136] Furthermore, the second flow control valve 160 is a one-way valve that prevents the flow of the fluid 124 from the front side to the rear side in the displacement direction of the flow control valve 240 when the integral displacement body 230 overcomes the elastic force of the return elastic body 218 and slides and displaces. Therefore, no flow of the fluid 124 occurs. Furthermore, the third flow control valve 170 is a valve that allows the flow of the fluid 124 in both the front and rear directions in the displacement direction of the flow control valve 240. Therefore, the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 240 with minimal flow resistance.

[0137] Therefore, the flow control valve 240 is displaced toward the cushioning material 221 a while generating a negligibly small damping force.

[0138] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and separated from the socket body 107 from the end of the integral displacement body 230, the integral displacement body 230 is displaced to its original position by the elastic force of the return elastic body 218, similarly to the first embodiment (see FIG. Figure 9 That is, the flow control valve 240 displaces toward the cushioning material 221b while generating a negligibly small damping force. As a result, the integral displacement body 230 slides toward the socket body 107 at a faster displacement speed than before.

[0139] Next, when the socket body 107 contacts the end of the integral displacement body 230 with a strong force (high speed), as shown in FIG. Figure 13 As shown, the integral displacement body 230 rapidly slides toward the rack housing 104 relative to the inner cavity forming body 211. That is, the flow control valve 240 rapidly displaces toward the buffer material 221a in the inner cavity 217 against the elastic force of the return elastic body 218.

[0140] In this case, the force exerted by fluid 124 on second flow element 156 is greater than the elastic force of separation elastic member 159, causing first flow control valve 150 to displace toward first flow element 153 and be pressed against it. Furthermore, in this case, first aperture restriction 155 and second aperture restriction 158 are formed at positions opposing second flow hole 157 and first flow hole 154, respectively, thereby blocking all of second flow hole 157 and a portion of first flow hole 154, respectively. Therefore, in first flow control valve 150, when flow control valve 240 is displaced toward rack housing 104, fluid 124 ceases to flow (see dashed arrow). Similarly, in this case, fluid 124 ceases to flow through second flow control valve 160, as described above.

[0141] Furthermore, the third flow control valve 170, of the flow control valves 240, is the only one that allows the flow of fluid 124, thus generating a significant flow resistance. Consequently, the flow control valve 240 overcomes this significant flow resistance and displaces toward the cushioning material 221a. This causes the integral displacement body 230 to slide toward the rack housing 104, generating a significant damping force. In other words, the damper 210 can dampen the strong impact generated by the rack bar 103.

[0142] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the socket body 107 is separated from the end of the integral displacement body 230, the integral displacement body 230 is displaced to its original position by the elastic force of the return elastic body 218 in the same manner as described above (see FIG. Figure 9 That is, the integral displacement body 230 is displaced toward the cushioning material 221 b by generating a negligibly small damping force through the flow control valve 240 , thereby rapidly slidingly displaced toward the socket body 107 .

[0143] And, when implementing the present invention, it is not limited to above-mentioned each embodiment, as long as do not depart from the purpose of the present invention, just can carry out various changes.In addition, in the description of each modification, to the part identical with above-mentioned embodiment, mark the same figure mark and omit repeated description.

[0144] For example, in each of the above-described embodiments, the first flow control valve 150 is configured such that the second aperture restriction 158 of the second flow body 156 partially blocks the first flow hole 154 of the first flow body 153, and the first aperture restriction 155 of the first flow body 153 completely blocks the second flow hole 157 of the second flow body 156. However, the first flow control valve 150 may be configured to block at least a portion of at least one of the first flow hole 154 and the second flow hole 157.

[0145] So, for example Figure 14 As shown, the first flow control valve 150 can also be configured to completely block both the first flow hole 154 and the second flow hole 157. In addition, the first flow control valve 150 can also be configured to block a portion of both the first flow hole 154 and the second flow hole 157. In this case, for example, Figure 15 As shown, the first flow control valve 150 can also be configured so that a portion of the first flow hole 154 and a portion of the second flow hole 157 overlap each other when the second flow body 156 is in close contact with the first flow body 153, thereby ensuring the flow of the fluid 124. Thus, the flow control valves 140 and 240 can be configured without the third flow control valve 170.

[0146] In addition, the first flow control valve 150 can also be configured to completely block one of the first flow hole 154 and the second flow hole 157 and not block the other. Figure 16 As shown, the first flow control valve 150 can have a first aperture restriction portion 155 formed in the bottom portion of the second flow body housing 151, opposite the small-diameter aperture 157b, that projects in a columnar shape toward the small-diameter aperture 157b (second flow hole 157). In this case, the second aperture restriction portion 158 of the second flow body 156 is omitted. Thus, the first flow control valve 150 can block only the second flow hole 157 by abutting the second flow body 156 against the first aperture restriction portion 155.

[0147] In addition, for example Figure 17 and Figure 18 As shown in each example, the first flow control valve 150 can also include a columnar second aperture restrictor 158 protruding toward the first flow hole 154 in the portion of the second flow body 156 that faces the first flow hole 154, thereby blocking only the first flow hole 154. In this case, the first aperture restrictor 155 in the first flow body 153 can be omitted. Furthermore, in this case, the columnar first aperture restrictor 155 and / or second aperture restrictor 158 can be inserted into the small-diameter hole 157b (second flow hole 157) and / or the first flow hole 154, thereby blocking each hole.

[0148] In the above-described embodiments, the second flow hole 157 is composed of two holes: a large-diameter hole 157a and a small-diameter hole 157b. However, the second flow hole 157 may be composed of a single hole, either the large-diameter hole 157a or the small-diameter hole 157b, or may be composed of three or more holes with different inner diameters. Furthermore, the second flow hole 157 has a tapered portion 157d formed at the opening of the small-diameter hole 157b on the side opposite the first flow element 153. This facilitates the flow of the fluid 124 into the second flow hole 157, stabilizing the operation of the first flow control valve 150. Furthermore, the first flow control valve 150 facilitates the flow of the fluid 124 into the second flow hole 157, thereby increasing the flow rate. Therefore, the tapered portion 157d exerts a strong pressure from the fluid 124, facilitating displacement of the second flow element 156 toward the first flow element 153. However, the second flow hole 157 may also be formed straight without the tapered shape. Furthermore, the first flow hole 154 may be composed of a plurality of holes that are different from each other, and the opening of the hole may be tapered.

[0149] In each of the above-described embodiments, the flow control valves 140 and 240 are configured to include a first flow control valve 150, a second flow control valve 160, and a third flow control valve 170, respectively. The second flow control valve 160 can increase the displacement speed of the flow control valves 140 and 240 during their return displacement. Furthermore, the third flow control valve 170 can ensure the flow of the fluid 124 while the second flow body 156 is in close contact with the first flow body 153, completely blocking the flow of the fluid 124. However, the flow control valves 140 and 240 can be configured to omit at least one of the second flow control valve 160 and the third flow control valve 170.

[0150] In the above-described embodiments, the dampers 120 and 210 are configured such that the first flow control valve 150 is disposed within the inner chambers 121 and 217, respectively. However, the dampers 120 and 210 may also be configured such that the first flow control valve 150 is disposed outside the inner chambers 121 and 217, respectively. Furthermore, the dampers 120 and 210 may also be configured such that the second flow control valve 160 and the third flow control valve 170 are also disposed outside the inner chambers 121 and 217, respectively.

[0151] In the above embodiments, the dampers 120 and 210 are respectively provided with the return elastic bodies 132 and 218. However, if it is not necessary to constantly press the flow control valves 140 and 240 toward one side of the inner cavities 121 and 217, the dampers 120 and 210 may be respectively provided with the return elastic bodies 132 and 218 omitted.

[0152] In the first embodiment, the socket body 107, which corresponds to the inner cavity forming body of the present invention, is formed of a solid rod. However, the socket body 107 can be formed according to the object to which the damper 120 is mounted, and can be formed into a cylindrical shape, for example.

[0153] In the second embodiment, the integral displacement body 230 is formed in a cylindrical shape. However, the integral displacement body 230 can be formed according to the object to which the damper 210 is mounted, and can be formed in a solid rod shape, for example.

[0154] In the above-described embodiments, the dampers 120 and 210 are applied to the steering devices 100 and 200. However, the dampers 120 and 210 can be attached to devices or appliances other than the steering devices 100 and 200, specifically, suspension mechanisms, seat tilt mechanisms, door opening and closing mechanisms, mechanical devices other than self-propelled vehicles, motor devices, appliances, or furniture.

[0155] Description of Reference Numerals

[0156] 100…steering device; 101…steering wheel; 102…steering shaft; 102a…pinion gear; 103…rack rod; 103a…rack gear; 104…rack housing; 105…intermediate connecting member; 106…rack ball joint mechanism; 107…socket body (inner cavity forming member); 107a…ball retaining portion; 107b…externally threaded portion; 108…stud body; 108a…ball portion; 110…tie rod; 111…steering knuckle arm; 112…wheel; 120…damper; 121…inner cavity; 122…wall forming member; 123a, 123b…Buffer material; 124…Fluid; 125a, 125b…Sliding bushing; 126a, 126b…Sealing ring; 130…Integrated displacement body; 131…Elastic body retaining portion; 132…Reset elastic body; 133…Dust cover; 134…Dust seal; 135…Accumulator housing; 136…Accumulator; 140…Circulation control valve; 141…Valve support; 142…Sealing ring; 150…First circulation control valve; 151…Second circulation body housing; 152…Anti-slip ring; 153… First flow body; 154…first flow hole; 155…first aperture limiting portion; 156…second flow body; 156a…large diameter portion; 156b…small diameter portion; 157…second flow hole; 157a…large diameter hole; 157b…small diameter hole; 157c…stepped portion; 157d…tapered portion; 158…second aperture limiting portion; 159…separation elastic body; 160…second flow control valve; 170…third flow control valve; 200…steering device; 201…dust cover; 210…damper; 211…inner cavity forming body ; 211a…external threaded portion; 212…oil supply port; 213…accumulator housing portion; 214…accumulator; 215, 216…wall forming body; 217…inner cavity; 218…resetting elastic body; 218a…support plate; 221a, 221b…buffer material; 222a, 222b…sliding bushing; 223a, 223b…sealing ring; 224a, 224b…dustproof seal; 230…integrated displacement body; 231…fixing sleeve; 240…circulation control valve; 241…valve support body; 242…sealing ring.

Claims

1. A flow control valve, provided in a flow path for a fluid to flow, which controls the flow of the fluid by restricting the flow of the fluid, characterized in that: have: a first flow body having a first flow hole for flowing the fluid; a second flow body disposed opposite to the first flow body and having a second flow hole for flowing the fluid; as well as The separation elastic body exerts elastic force to separate the first circulation body and the second circulation body from a position where they are in contact with each other. At least one of the first flow body and the second flow body includes an aperture restriction portion. The aperture restriction portion blocks at least a portion of one of the second flow hole and the first flow hole when the first flow body and the second flow body are in contact with each other. The aperture restriction portion is formed to completely block the other of the second flow hole and the first flow hole.

2. The flow control valve according to claim 1, characterized in that The aperture limiting portion is provided only on one of the first flow body and the second flow body.

3. The flow control valve according to claim 1, wherein: The aperture limiting portion is provided on both the first flow body and the second flow body.

4. The flow control valve according to any one of claims 1 to 3, characterized in that: The device further comprises a second flow body accommodating portion that accommodates the second flow body on the second flow body side so as to be movable relative to the first flow body. The separating elastic body is provided between the first communicating body and the second communicating body in the second communicating body accommodating portion.

5. The flow control valve according to any one of claims 1 to 3, characterized in that: The opening of the second flow body on the opposite side of the first flow body in the second flow hole is formed into a tapered shape in which the size of the hole decreases from the opening side toward the inner side.

6. The flow control valve according to any one of claims 1 to 3, characterized in that: further comprising a one-way valve for allowing the fluid to flow through a flow path different from the first flow body and the second flow body, The one-way valve allows the fluid to flow from the first flow-through body side toward the second flow-through body side and prevents the fluid from flowing from the second flow-through body side toward the first flow-through body side.

7. The flow control valve according to any one of claims 1 to 3, characterized in that: further comprising a flow restriction valve configured to restrict the flow of the fluid through a flow path different from the first flow body and the second flow body, The flow restriction valve restricts the flow of the fluid between the first communication body side and the second communication body side to allow the fluid to flow.

8. A damper comprising an inner cavity forming body constituting an inner cavity for liquid-tightly accommodating a fluid, wherein an external force applied to the fluid is attenuated by restricting the flow of the fluid, characterized in that: A flow control valve according to any one of claims 1 to 7, The flow control valve allows the fluid to flow while restricting the flow.

9. The damper according to claim 8, characterized in that The flow control valve further includes a return elastic body that applies elastic force for causing the fluid to flow from the first flow body side to the second flow body side in the flow control valve. The flow control valve is disposed in the inner cavity in a state where it can be displaced relative to the inner cavity. The resetting elastic body applies the elastic force to one of the inner cavity forming body and the flow control valve to displace the one relative to the other.

10. The damper according to claim 9, characterized in that It also includes an integral displacement body, which is relatively displaced integrally with the flow control valve relative to the inner cavity. The inner cavity forming body is formed into a solid rod or cylinder shape, The inner cavity is formed in a circular cylindrical shape on the outer side of the inner cavity forming body. The flow control valve is formed on an annular valve support body, and the annular valve support body is embedded in the inner cavity of the annular cylinder. The integral displacement body is formed in a cylindrical shape so as to be slidably fitted into the inner cavity forming body.

11. The damper according to claim 9, characterized in that It also includes an integral displacement body, which is relatively displaced integrally with the flow control valve relative to the inner cavity. The inner cavity forming body is formed into a cylindrical shape, The inner cavity is formed into a circular cylindrical shape inside the inner cavity forming body. The flow control valve is formed on an annular valve support body, and the annular valve support body is embedded in the inner cavity of the annular cylinder. The integral displacement body is formed in a solid rod or cylindrical shape and is slidably fitted into the inner cavity forming body.

12. A steering device comprising: A steering shaft, formed by extending into a rod shape and rotated by operation of the steering wheel; A rack rod is formed by extending into a rod shape and converting the rotational motion of the steering shaft into reciprocating motion in the axial direction for transmission; an intermediate connecting body connected to both ends of the rack bar and directly or indirectly connected to wheels to be steered with respect to the both ends; and a rack housing, covering the rack rod, The steering device is characterized in that A damper according to any one of claims 8 to 11, The damper is provided between the rack housing and the rack bar or the intermediate connecting body to absorb impact from the wheel.

13. The steering device according to claim 12, characterized in that When the damper provided is the damper according to claim 10, The inner cavity forming body is formed in the intermediate connecting body, The integral displacement body is formed at a position where it comes into contact with or is separated from the rack housing by the reciprocating motion of the rack bar.

14. The steering device according to claim 12, characterized in that When the damper provided is the damper according to claim 11, The inner cavity forming body is formed at the end of the rack housing. The integral displacement body has the rack bar or the intermediate connecting body passing therethrough, and is formed at a position where it contacts or separates from the rack bar or the intermediate connecting body due to the reciprocating motion of the rack bar.

Images